Biology unit 20 Flashcards
Food production part 1
Agricultural machinery has replaced humans and improved efficiency due to the ability to farm much larger areas of land
Chemical fertilisers improve yields - fertilisers increase the amount of nutrients in the soil for plants, meaning that they can grow larger and produce more fruit.
Food production part 2
Insecticides and herbicides - these chemicals kill off unwanted insects and weed species, meaning that there is less damage done to plants and fruit lost to insects, as well as reducing competition from other plant species (herbicides)
food production part 3
Selective breeding - animals and crop plants which produce a large yield are selectively bred to produce breeds that reliably produce high yields
Advantages of large scale monocultures of crop plants
It makes farming much more efficient, keeping costs down. Machines and procedures can be used totally systematically on a large scale.
Disadvantage of large scale monocultures of crop plants
increased vulnerability to pests and diseases. When a single crop is grown over a large area, it creates an ideal environment for pests and pathogens that can devastate the entire crop.
Advantages of intensive livestock production
The cost of production is lower
therefore food can be sold at cheaper prices
There is a lower requirement for labour to produce the food
Disadvantage of intestive livestock production
Ecological issues with the reduction in biodiversity in areas where large amounts of land are used to graze cattle
Intensive farming techniques tend to use
- pesticides which can cause negative effects on the foodchain
Describe biodiversity
as the number of different species that live in an area
Reasons for habitat destruction
- marine pollution - eutrophication can occur when fertilisers from intensively farmed fields enter waterways, causing high decrease in biodiversity as most aquatic species living there die from lack of oxygen
Reasons of habitat destruction part 3
- extract of natural resources- many trees are cut down to create products destroying forest habitats. In addition some resource extraction takes up a large amount of space
Reasons of habitat destruction - Clearing land for farming and housing
Crops, livestock and homes take up a large amount of space
As there is an increase in population in demand for food, the amount of land available for these things must be increased by clearing habitat e.g forest
Describe a sustainable resource
as one which is produced as rapidly as it is removed from the environment so that it does not run out
Why organisms become endangered or extinct part 2
This not only reduces their numbers but can also disrupt ecological balance, affecting other species that rely on them for food or other ecological functions. Pollution introduces harmful substances into ecosystems, affecting air, water, and soil quality, which can lead to health problems in wildlife and a decline in species populations. This invasive nature can lead to a decline in biodiversity, as native species struggle to survive in the face of these new competitors .
Process of eutrophication of water
Runoff of fertiliser from farmland enters the water and causes increased growth of algae and water plants
The resulting ‘algal bloom’ blocks sunlight so water plants on the bottom start to die, as does the algae when competition for nutrients becomes too intense
As water plants and algae die in greater numbers, decomposing bacteria increase in number and use up the dissolved oxygen whilst respiring aerobically
As a result there is less oxygen dissolved in water, so aquatic organisms such as fish and insects may be unable to breathe and would die
Explain how tree be conserved
replanting similar/same trees when mature trees are cut, ensuring that there will be adequate supply in the future
Education helps to ensure logging companies are aware of sustainable practices and consumers are aware of the importance of buying products made from sustainable sources
Explain how fish stocks can be conserved
Controlling the time of year that certain fish can be caught (to prevent large scale depletion of stocks when fish come together in large numbers in certain areas to breed)
Restocking (breeding and keeping offspring until they are large enough to survive in their natural habitat then releasing)
Educating everyone so they are aware of types of fish which are not produced sustainably and can avoid them when buying fish
Effects of non biodegradable plastics - aquatic
Animals often try to eat plastic or become caught in it, leading to injuries and death. As the plastic breaks down it can release toxins that affect marine organisms. Once it has broken down into very small particles, it is commonly ingested by animals and enters the food chain
Effects of non bioplastics - ecosystem
Plastic is generally disposed of by burying in landfills. As it breaks down, it releases toxins into the surrounding soil and as such the land is no good for growing crops or grazing animals and can only be used for building on several decades after burial
Flooding and extinction/loss of biodiversity
- flooding - without trees the topsoil will be loose and unstable so will be easily washed away by rain, increasing the risk of flash flooding/landslides
- extinction - forest habitats have a huge range of biodiversity, but as it’s getting destroyed at a fast rate, it causes the loss of numbers of plant/animal species that are only found in these areas and therefore will become extinct.
Soil erosion
- trees will usually take up nutrients and minerals from the soil through their roots. The loss of soil nutrients is permanent and makes it very difficult for forest trees to regrow, even if the land is not cultivated with crop plants or grass.
Increased co2 in atmosphere
- when areas of land in forests are cleared for land use, the trees often as opposed to being cut down, this further increases the co2 levels in the atmosphere, contributing to global warming.
Resources conserved
some resources can be conserved and managed sustainably, limited to forests and fish stocks
How endangered species can be conserved
education programmes
captive breeding programmes
monitoring and legal protection of the species and of their habitats
seed banks as a conservation measure for plants - seeds of endangered plant species are carefully stored so that new plants may be grown in the future
reasons for conservation programmes part 1
- Maintaining or increasing biodiversity
Which allows ecosystems to remain stable - Reducing extinction - Helps to retain iconic species and maintain biodiversity
- Protecting vulnerable ecosystems which would have been quickly lost to human activity.
Reasons for conservation programmes part 2
- Maintaining ecosystem functions
Nutrient cycling eg. carbon cycling to hold back climate change
Resource provision, such as
Food - making sure we have enough for the population
Drugs - having access to plants for plant-based remedies
Fuel - for improtant activities such as cooking
Genes - so the gene pool remains wide and variety exists in all species
The risk to a species if it’s population size decreases
If its population size decreases, a species will experience reduced genetic variation
This renders the species more susceptible to environmental change
The species is less resilient and has a greater risk of extinction
IVF and AI in captive breeding programmes
Artificial insemination (AI), allows large numbers of offspring to be produced without the need for conventional sexual intercourse between males and females
In vitro fertilisation (IVF)
This allows gametes with known alleles to be used in ensuring the next generation remains biodiverse
